Calcitonin receptor gene polymorphism in Japanese women: Correlation with body mass and bone mineral density

We have identified a polymorphism at position 1377 of the calcitonin receptor (CTR) gene which generates CC, CT, or TT genotype. In this study, the genotypes of the CTR and their relationship with the body height, the body weight, the bone mineral density (BMD), and osteocalcin levels were examined in 152 healthy Japanese women aged 16-43 years. The CTR genotypic frequencies in the Japanese population were 77.0% for CC, 20.4% for CT, and 2.6% for TT. The height, BMD, and osteocalcin levels were not significantly different among these three genotypes. The body weight adjusted for height in these three groups was significantly different in the order of TT, CT, and CC (P = 0.0454 by analysis of covariance). In combined analysis of the VDR genotype (B,b) and the CTR genotype (C,T), the body height was found to be significantly different between CCB and others (P = 0.0236). In addition, analysis of the CTR genotypic frequency using 64 blood samples from Japanese and 47 blood samples from Caucasians indicated that there was a significant difference between the two races (P < 0.0001). We found that C allele was predominant in the Japanese population, however, Caucasians have an almost equal ratio of the C and T. In conclusion, the CTR allele is one of the genetic factors regulating body weight in Japanese women.